I get a disturbing jolt of power as I roll onto my throttle after engine braking. It feels like there is a TON of chain slack or a destroyed cush drive. Both the chain and the cush drive are fine. Its getting to the point where getting back into the throttle in a turn feels like the back tire could break traction. Needless to say I dont feel too safe riding my bike. What could be the problem? Worn gears? Beat up dogs? (I've never heard grinding and its never popped out of gear). It hasn't always been like this. Any help would be appreciated!